As therapeutic nucleic acid molecules begin to enter clinical trials, the need for methods of in vitro nucleic acid analysis and in vivo nucleic acid detection is essential. Thus, as nucleic acid therapeutics progress through preclinical studies and into clinical trials, there is a need for reagents capable of detecting such molecules in fluids (e.g., whole blood, plasma, spinal fluid and the like), cells, tissues, tissue samples and the like. For preclinical studies, addition of tags such as 2′-bromo-deoxyuridine (BrdU) and fluorescein to the nucleic acid molecule during synthesis is useful for localization studies. In clinical trials, however, nucleic acid molecules administered therapeutically do not carry such tags. Therefore, other methods of detection and analysis need to be developed in order to assay nucleic acid-based therapeutics in a bioanalytical clinical setting.
Antibodies are highly specific and efficient analytical tools that can be used in biomedical research. Modern researchers have capitalized on this bioanalytical tool through a variety of modification techniques, including antibody engineering using recombinant DNA methods. The use of antibodies has expanded from simple diagnostic assays to the detection of molecular structures, the elucidation of gene function, the localization of gene products, and the rapid screening of biological effectors for drug discovery and testing. The use of such antibodies with fluorescent or enzymatic tags, in concert with advances in microscopy, has resulted in improved enzyme-linked immunosorbent assay (ELISA) systems. The use of ELISA based microarrays with antibodies promises to transform current paradigms of disease research and the search for new therapeutic compounds. Moreover, antibodies can also serve not only as powerful research tools, but also as therapeutic compounds when conjugated with modifications such as radioisotopes and/or other chemotherapeutic compounds.
In recent years antibodies have become well characterized through experimentation and manipulation. The typical antibody is a tetrameric molecule comprising two copies of a heavy chain (H) polypeptide which is approximately 440 amino acids long and two copies of a light-chain (L) polypeptide which is about 220 amino acids long. Each antibody-based H and L polypeptide contains a variable region and a constant region. At the terminus of each arm of the Y-shaped antibody exists a site comprising the variable termini of the H and L subunits, which together bind to a specific and unique site on an antigen, otherwise known as an epitope. Antibody technology has developed from the production and use of polyclonal antibody mixtures derived from rabbits and horses to the production of specific monoclonal antibodies through cell fusion techniques using mice spleens and cancers, to modern engineering of uniquely designed mono and divalent antibodies. Chimeric antibodies are created when the antigen-binding component of a one antibody, such as a mouse antibody, is fused to the effector component of another antibody, for example a human antibody, using genetic engineering. Monoclonal antibodies originally raised in mice, rabbits, pigs, sheep, cows, horses or the like can also be “humanized” by exchanging surface-exposed amino acids, which can be determined through molecular biological (e.g., sequencing), crystallographic and molecular modeling techniques, found on the non-human antibody to those more often found in human antibodies. Also, mice have been developed that harbor human antibody-producing elements and major histocompatibility complexes (MHCs) in place of the corresponding murine elements and complexes, such that immunization of these mice leads to the direct generation of human antibodies in the mouse. Antibodies can also be fused with a variety of other proteins that can modulate both antibody activity and localization for specific applications.
The antibodies described herein are unique and distinct from previously described antibodies. Furthermore, antibodies of the present invention are useful in a variety of applications, including but not limited to bioanalytical assays supporting clinical trials, screening candidate therapeutic molecules for optimum bioavailability and/or activity in vivo, and the in vivo delivery of certain nucleic acid molecules to specific cells or tissues.